Apparatus for dislodging surface materials



Oct. 22, 1940. T. J. BALL APPARATUS FOR DISLODGING SURFACE MATERIALS 2 Sheets-Sheet l Filed Dec. 15, 1938 1160?. Z $93G (J Oct. 22, 1940. T. J. BALL APPARATUS FOR DISLODGING SURFACE MATERIALS 2 Sheets-Sheet 2 Filed Dec.

(I Om Patented Oct. 22, 19 40 pair orrics APPARATUS FOR DISLODGING SURFACE MATERIALS Thomas J. Ball, Boston, Mass.-

12 Claims.

Ihe present invention relates to apparatus for dislodging surface materials. More particularly, the present invention relates to such apparatus driven by a'power vehicle and equipped with a main dislodging blade or mold board construction which is pivoted either at an end or at any point between its ends and is swingable about the pivot by power means during continuous progress of the apparatus. For purposes of disclosure only, the material to be dislodged will be considered as being snow,'and the apparatus illustrated in the drawings. and described herein is 'a snow plow, but it will be understoodthat the invention is not limited to the dislodging of snow nor to snow 15 plow apparatus.

In the continued use along a street or roadbed of snow plow apparatus, the dislodging blade or mold board of either type characterized above is.

normally disposed diagonally of the line of progdesirable that th blade be located transversely of the line of progress, and examples of these situations are the intersections with the street or roadbed being plowed of other streets, roadbeds, driveways, cross walks, and the like. The reason why the blade is desirably disposed transversely of the line of progress in such situations is that considerably less snow is spilled off a given edge of the blade than flows over that same edge when it is a trailing edge, i. e., when the blade is diagonally disposed, and hence less. snow is ridged up across the intersection. It should be pointed out, however, that dislodging blades are not always swung merely to a transverse position, 40 but are sometimes swung past it. Examples of blades thus swung are those of the reversible type the function of which is to completely change the very kind or plowing, i. e., to change snow delivery off the right hand edge, for exampie, to delivery oii the left hand edge, and'vice versa, during continuous plowing.

By reason of the dislodging blade being variously pivoted as stated above, it may be swung to a transverse position with respect to the line of progress, or be swung from such a position, or be swung to or from any one of a plurality of diagonally disposed positions, and since the most economical plowing is generally that which is continuous, it is becoming customary today to provide that this swinging be done by hydraulic ress so that the blade has a leading edge, a trail- Application December 15, 1928, Serial No.245,934

ram'constructions which are of an extremely quicl -acting type. By such an arrangement for blade swinging, the power vehicle to which the blade is connected neednot stop or even slow down at intersections but may continue its even 5 progress if cross trailic conditions permit. These quiclr-acting'rarns are actuated by a continuously operating power pump ,for the fluid (oil), and such actuation is to be carefully distinguished from the slow actuation by means of a 10 manually operated pump such, for example, as the common type mounted in the cab of the power vehicle and having a pivoted lever which an operator manually oscillates to develop and apply pressure at spaced intervals of time and 15. not continuously as with a power pump.

But however desirable quick-acting blade swinging may be so far as plowing itself is con cerned, and it will be understood that the blade may be swung from a diagonal position to a 20, transverse one, or to a reverse diagonal one, at points other than intersections, this blade swinging produces an undesirable and dangerous situation for traffic on the street or roadbed being plowed. Bearing in mind that since a pivoted blade or mold board always produces the widest plowing path when located transversely of the line of progress, it will'be seen not only that when the blade is diagonally disposed it produces a narrower plowing path but also that when a diagonallydisposed blade is swung to transverse position, the width of the plowing path necessarily increases. This is just as true for a blade pivoted at an end as it is for a blade pivoted at its center or at some other point between its ends.

This increase in plowing path width as the blade approaches and reaches a transverse position is caused by the blade itself occupying an increasingly greater transverse footage of the street or roadbed being plowed, and when the blade actually, reaches a transverse position, in which case the transverse footage occupied by it is maximum, the blade generally extends well beyond one or both sides of the power vehicle used to cause the plowing apparatus to progress. The reason why there is danger to traific under these conditions is that since this increase in the transverse footage occupied by the blade occurs almost instantly with the power actuated ram constructions now in use, the driver of any motor vehicle who is gauging his own position on the street or roadbed being plowed by the posi-- tion transversely of that street or roadbed of the leading edge of a diagonally disposed blade if right hand plowing is taking place or of the near side of the power vehicle which causes the blade to progress, may find himself directly confronted with an end portion of a blade so suddenly become transverse that a collision with the blade can not beavoided. The danger of such a collision is always present even if the driver of the motor vehicle is a careful driver, but independently of this the danger is also present when a street is relatively narrow and there is even normal trafiic or where there is much traific regardless of street width. The collision may be with a motor vehicle going in the same direction as the plowing apparatus and being near it laterally and attempting to pass it, or, if the apparatus is adjacent the center of the street or roadbed and traffic is heavy, there may be a collision with a motor vehicle going in the opposite direction and located near the center of the street or roadbed. Such a collision might cause other motor vehicles to be damaged, and in all these possibilities of accident it must be remembered that whether snow is still falling while plowing is taking place or whether the snow has stopped falling, motor vehicle traffic in snow or ice conditions is at all times dangerous and unsure, and is never normal.

It being appreciated that for continuous plowing it is very desirable that blade swinging takes place very rapidly, and it being further appre ciated that the danger of accidents pointed out above arises by reason of the dislodging blade or mold board very suddenly occupying an increased transverse footage of the street or roadbed being plowed, it is the principal object of the present invention to prevent such danger while permitting such quick swinging by providing a dislodging apparatus such that the transverse footage occupied by a dislodging blade or mold board when located transversely of the line of progress shall never exceed the transverse footageoccupied when the blade or mold board is located diagonally of the line of progress.

To the accomplishment of this principal objectand of such others as may hereinafter appear, the present invention resides in certain constructions, combinations, and arrangements of parts fully described hereinafter and then pointed out broadly and in detail in the appended claims.

The various features of the present invention will be readily understood from inspection of the accompanying drawings illustrating the best physical embodiment of the present invention at present known to the inventor, in which:

Figure 1 is a view in plan of an embodiment of the present invention;

Fig. 2 is a view in rear elevation, partially in section, of the mold board and mold board extension construction, taken along the line 22 of Fig. 1; and

Fig. 3 is a view in sectional elevation taken generally along the line 33 of Fig. 1.

As will be apparent hereinafter, the present invention contemplates that the di lodging blade or mold board may be pivoted either at one end or at any point between its ends. For mere illustrative purposes, however, the embodiment of the present invention shown in the drawings employs a mold board pivoted at one end, specifically the right hand end with regard to the line of progress indicated by the arrow A in Fig. 1.

Referring more particularly to the drawings, the illustrated embodiment of the present invention is provided with a mold board 50 comprising the usual dislodging blade H from the lower portion of the front face of which there depends.

the usual scraper blade 62 (Figs. 2 and 3). As the blades If and i2 are functionally a unit for material dislodging purposes, I intend that in the appended claims reference to dislodging blade or blades should not be interpreted so as to exclude a scraper blade. The mold board it is substantially rectangular in front and rear elevation, as indicated in Fig. 2, while in side elevation (Fig. 3) it is forwardly curved along substantially its upper half to present the usual concave front face possessed by mold boards in general,

In order to form an abutment for the mold board l0 when it is located transversely of the line of progress, as shown in construction lines in Fig. l, and also in order to provide a convenient pivot about which the mold board may be swung to and from a suitable location diagonal of the line of progress, as shown in full lines in Fig. 1, the illustrated embodiment of the present invention is provided with a push frame construction indicated generally by the numeral $3 in Fig. 1. Describing the push frame I3 in more detail, it is provided with a flat, substantially rectangular plate it having at its front end a channel iron arm l5 the outer surface of one leg of which rests on the plate It so that the web of the arm I5 is vertical and preferably coterminous with the front edge of the plate l4. Further push frame structure includes two longitudinal angle iron braces l6 and 51 located one at each side of the plate Hi, and a rear angle iron brace 18. The channel iron arm 05 extends to the right (Fig. 1) of the plate 14 a sufficient distance to be substantially coterminous with the right hand (Fig. 1) end of the mold board it) when in its intended position on the apparatus transversely of the line of progress, and the free end of the arm I5 is provided with one leaf Id of a hinge 20 having an eye 2| (Fig. 2). The right hand end portion of the mold board if is provided at its rear (Fig. 2) with a hinge leaf 22 having an eye 23, and a pin 2% extending through the two eyes serves to connect the mold board to the push frame and to provide a pivot about which the mold board may be swung. The hinge leaves I!) and 22 are shown as countersunk in the mold board 19 and the push frame arm l5, respectively, although it will be clear that any other suitable hinge arrangement may be used. Where countersinking is used, it is preferred that the material of the arm 15 back of the hinge leaf l9 be strengthened, as by a plate 25. By reason of the particular hinge structure shown, it will be apparent that when the leaves l9 and 22 are parallel, in Which situation the mold board i0 is located transversely of the line of progress, the portions of the mold board It opposite the push frame arm [5 will be spaced therefrom and that the hinge leaves l9 and 22 will themselves be spaced apart. To provide the abutment feature of the push frame referred to above, the arm l5 may be provided with vertical abutment plates 26 mounted flatwise on the verticalfront face of the arm and having a thickness equal to the width of the space between the arm and the mold board if) when the latter is located transversely of the line of progress. The above-described construction thus provides that when the mold board it is located transversely of the line of progress, the push frame it, acting through the plates 26, exerts a forward pushing against the rear of the mold board and also pro- Vides that the mold board may be swung at its 2,218,512 right hand end (Fig. 1) so as to be diagonally disposedto the line of progress; j i

It will be appreciated that in snow plow constructions push frames-are generally provided with casters and that. at the front of the power vehicle which drives the plowing apparatus a framework is provided on which or from which mechanism is supported for lifting and lowering the mold board and push frame, for equalizing.

weight at opposite sides of the center line, and

tachment to the framework portions customarily designed for this purpose. i

line) position. By reason of this fact it will be mold board normally located diagonally of the line of progress is swinging to' a position trans verse of that line, the width of the plowing path,

which it is seen that the left hand edge of the mold board If! shown diagonally located in full lines is spaced inwardly from the line indicating the left hand edge of theplowing path of the mold board when in transverse (construction seen that if the mold board it were the entire snow dislodging structure, the plowing path would increase steadily as the mold board moved,

rearwardly to its Fig, 1 construction line position.

In order to prevent this result, that is, in order to, provide material dislodging apparatus of such nature that the transverse footage occupied by the mold board ordislodging blade construction when located transversely of the line of progress shall never exceed the transverse footage occupied. when the mold board or dislodging blade is located diagonally of the line of progress, and as a consequence to prevent the occurrence of accidents referred to above, the present invention contemplates the provision of an auxiliary mold board or dislodging blade extension or construction which is slidable along the mold board and swingable therewith, and further contemplates the provision of means for generally by the numeral 28 and comprising a dislodging blade from the lower portion of the front face of which there depends a scraper blade 33; As the blades 29 and 30, like the blades H and H2, are functionally a unit for material dislodging purposes, I also intend that in the appended claims reference to ,dislodging blade or blades should not be interpreted so as to exclude a scraper blade. The second or extension mold board construction 23 has the same generally forward concavity as the mold board If), and the top of the blade 23 is substantially coterminous with the top of the blade H. The blade 28, however, does not extend down as far as does the blade ll, and preferably rests on the top of the scraper blade l2 so as to besupported thereby. Asshown best in Figs. 1 and 2, the blades 29 and 30 engagingly overlap the front faces of the blades II and I2, respectively, the

'former pair extending longitudinally by about half their length beyond the left hand (Fig. 1) I edge of the mold board In when in its full line,

diagonal position there shown.

In order to secure to the mold board Ill the extension 28 formed by the blades 29 and 30, so

that the extension is slidably movable along the mold boards front face, the blade H is provided at its left hand (Figs. 1 and 2) portion with a 7 h wardly of the blade 29 each stud 33 is provided It has been pointed out" above that while a with a laterally elongated portion'3 adapted to be slidably received by its associated slot 3| in engagement with the opposite walls thereof and having end portions shaped correspondingly with the ends of the slot. Rearwardly of its elongated portion 34 each stud is provided with a shank 35 which extends through an opening formed in a curved brace 36 engaged with the rear face of the blade H and held slidably in position by nuts 31 threaded on the shanks 35. By reason of the above-described construction it will be seen that the mold board extension 28 is engagingly secured to the mold board if] and is slidable therealong to the extent determined by the length of the slots 3! and of the laterally elongated portions 34 of the studs 33. It will also be seen that by reason of the blade 29 resting on the scraper blade [2 the studs 33 function primarily to maintain the blade 29 engaged with the blade II and to permit their relative longitudinal sliding movement and are not relied upon in the illustrated embodiment of the present invention to support the weight of the blades 23 and 3|].

In order to swing the mold board llland its extension 28 as a unit or whole about the pivot afforded by the hinge 20, the illustrated embodiment of the present invention is provided with a somewhat diagrammatically shown hydraulic ram structure 38 of the well known push-pull type purchasable in the open market. Rams of this type have a cylinder such as indicated by the numeral 39 in Fig. 1, the rear end of which is provided with an ear 4!! for pivotal attachment to an arm of a bracket 4| mounted on the push frame plate l4, and the cylinder 39' extends forwardly and somewhat to the right and contains a piston 42 to which is secured the rear end of a ram rod 43. The rod $3 is reciprocable for the greater part of its length into and out of the cylinder 39, and the forward or free end of the rod 431s apertured and is received between the apertured cars 4 of a bracket 45 secured to the back of the blade l I. A pin .43 extending through.

the apertures in the ears M and the rod 4-3 pivotally secures the latter to the former. The stroke of the piston d2 is less than the internal. length of the cylinder 39 by reason of suitable stops (not shown) and adjacent its opposite ends the cylinder 39 is provided with fluid tube fittings t! and 68. With this construction the filling of the cylinders 39 withfluid entering on one side 1 line of progressor to a'transverse position, respectively.

In order to slide the mold board extension 23 along the front face of the mold board It], the rear face of the mold board is provided above and to the left of the bracket 45 with a somewhat diagrammatically shown hydraulic ram structure 49. This ram is also of the same well known push-pull type as the ram 38, differing therefrom only in being smaller because it does not have so much work to do. The cylinder 50 of the ram 49 is provided with ears 5i by which it may be bolted to the rear face of the mold board it, and as shown best in Fig. 2 is horizontal. The cylinder 50 contains a piston 52 to which is secured at one end a ram rod 53 reciprocable for the greater partof its length into and out of the cylinder 55, and the free end of the rod 53 is ap-- ertured and is received between the apertured' ears 54 formed on the brace 36. A pin 55 pivotally connects the rod 53 and the ears 54 together, and adjacent its opposite ends the cylinder 50 is provided with fluid tube fittings 56 and 5'! between which the piston 52 operates as is the case with the ram 38. With this construction the filling of the cylinder 55 with fluid entering on one side or the other of the piston 52, as will be described, will cause the piston to push the rod 53 out of the cylinder 50 or pull it in, as the case may be, and will therefore cause the mold board extension 28 to slide out to its Fig. 1 full line position or to slide in to its Fig. 1 construction line position, respectively. As will be shown below, the present invention contemplates that the ram rods 43 and 53 shall move out of or into their cylinders together.

In order to actuate the rams 38 and as so that their pistons 42 and 52, respectively, undergo movement to effect the swinging and sliding re ferred to above, the illustrated embodiment of the present invention is provided with a fluid reservoir R, a power pump P, a valve construction V, and piping and tubing, as will be described. The reservoir, pump, and valve are illustrated only diagrammatically in the drawings because they are all old and widely known constructions, but it may be stated that the reservoir and pump areconveniently mounted on the motor vehicle (not shown). The valve -V is carried in the cab, for

example, (not shown) and is illustrated as being of the well known four-way type employing a single handle 58 movable either to (1) a neutral position, or to (2) a forward position in which one valve nipple, St, is open to permit the flowing out of fluid under pressure while the other valve nipple, 59, is open to the reservoir and receives returning fluid for passage to the reservoir, or to (3) a rearward position in which the nipples 59 and 60 function reversely to what occurs when the handle 58 is in forward position. The valve V is provided with an outlet connected by piping 6! to the reservoir R, the reservoir is connected by piping 62 to the pump P, and the pump is connected by piping 63 to the pressure side of the valve V.

In order that fluid may be conveyed under pressure to the corresponding opposite ends of the cylinders 39 and 50, the fluid nipples 59 and 60 of the valve V are provided with Ys 64 and 55, respectively. Regarding the pistons 42 and 52 as being in suchposition that their rods 33 and 53 are extended, as shown in Fig.1, and further regarding the valve nipple 59 as being the passage out of which fluid flows under pressure when the lever 58 is moved to its forward position, the ends of the Y 64 receive the ends of lengths of tubing 65 and 51, respectively, the opposite ends of which are received, respectively, by the fitting 56 on the small cylinder 50 and by the fitting 47 on the large cylinder 39. With this arrangement the V 65 on the valve V receives the ends of lengths of tubing 68 and 69 the opposite ends of which are received, respectively, by the fitting 51 on the small cylinder and the fitting 58 on the large cylinder. With the hydraulic system full of fluid, it will therefore be seen that a. pushing forward of the handle 58 causes the outflow of fluid from the nipple 59 and the Y t l through the tubing lengths 55 and 67! to push the pistons so that the rods 53 and 43 occupy the positions shown in Fig. 1 and that simultaneously the fluid on the other side of the pistons is caused by their movement to flow out through the fittings 5? and 48 and through the tubing lengths 68 and 69 for reception by the Y 65 and the nipple 69 and passage through the piping 5! to the reservoir R. The mold board it and its extension 28 are thus caused to be swung as a unit or whole to the diagonally disposed position shown in Fig. 1 in full lines, and the extension 28 is thus caused to simultaneously slide outwardly along the mold board it} to the position shown in Fig. l in full lines. By pulling the handle 55 to its rearward position, the fluid takes courses just the opposite of those just stated, with the result that the ram rods 43 and 53 are withdrawn into their cylinders so that the mold board ill assumes the transverse position shown in construction lines in Fig. 1 and the extension 28 assumes simul taneously the retracted position also shown in construction lines in Fig. 1.

In View of the fact that the cylinder 39 is larger than the cylinder 55 and in view of the further fact that the stroke of the piston 43 is longer than that of the piston 53, it will be seen that if the two pistons are to make corresponding full strokes during the same time interval, i. e., simultaneously, provision must be made whereby more fluid enters the cylinder 39 than enters the cylinder 50 during the same time interval, and a corresponding provision must be made for fluid leaving the cylinders. Since the pressure source for the two cylinders is the same, i. e., as the pump P, the simultaneity of stroke completion of the two pistons during a given time interval is easily provided by giving to the littings M, 38, 55, and 5?, or to the arms of the \s fi l and 55, or to the tubing connection fittings on the arms of the Ys, difierential passage or opening sizes so that during a given time interval fluid flows in greater volume into and out of the opposite ends, respectively, of the cylinder 39 than flows into and out of the corresponding opposite ends, respectively, of the cylinder 50. As this is a well understood principle of hydraulics no specific size difierentials are shown in the drawings.

With reference to Fig. 1 it will be seen that the portion of the extension or auxiliary mold board 28 which projects beyond the leading or left hand edge of the main mold board In is of such length that the plowing path of the mold board it and the extension 28 as a unit or whole when they are in the diagonal, full line position of Fig. l is the same as the plowing path of the mold board Iii alone when transverse to theline of progress, as shown in construction lines in Fig. 1. This is a mere coincidence. An auxiliary mold board or extension might well extend outwardly farther than that shown or the length of sliding movement outwardly from the right hand ends of the slots 31 might well be longer thanthat shown, or both'of these factors might,

Given proper and corresponding exist together. volume flow for the particular cylinders used, the situation would be one in which, with the mold board it located transversely of the line of progress, the auxiliary mold board would correspondingly extend beyond the free end of the mold board if! and the width of the plowing path would merely be greater than that shown in Fig. 1 ortherewould bea situation in which the width of the plowing path of the mold board ill and the extension when diagonally disposed would be greater than their plowing path when transversely disposed. There is no limit, theoretically, to how far an auxiliary mold board may extend outwardly ofthe main mold board or how far the auxiliary mold board may slide outwardly-and inwardly so long as the width of the plowing path of the main and auxiliary mold boards as a unit or whole when disposed transversely of the line of progress does not exceed the width of the plowing path of the same elemen-ts when they are diagonally located.

In view of the foregoing it is not seen that much more need-be said concerning the operation of an embodiment of the presentinvention. The mold board I and the mold board extension 28 may be normally disposed angularly during continuous plowing as shown in full lines in Fig. 1, the particular angularity shown being merely illustrative and not by way of i any limitation exceptthat it should not be more than 45 from a linetransverse to the line of progress. Should it be desirable to oause the mold board it to be located transversely, the handle 58 is pushed forward, whereupon the mold board it almost instantly becomes so located, the ram 39 swinging slightly to the right, as indicated by the showing of the bracket $5 in construction lines in Fig. 1. Simultaneously with this change of positionof themold board Ill, the mold board extension 28 is withdrawn from its extended position, this withdrawing or retracting taking place proportionately to the swinging of the mold board and during the same time interval until is gauging his own position on the street or roadbed being'plowed by the transverse location of the leading edge of the mold board construction as a whole,'or by the near side of the power vehicle pushing it, to collide with a dislodging blade or mold board construction suddenly become transverse and extending into his own line ofprogress, The driver and his motor vehicle are spaced sufficiently far away at the very start to prevent a collision, and soboth are safe from injury.

The illustrated embodiment of. the present invention has been shown as set up for right hand plowing when the mold board H1 is diagonally located merely because in the United States traffic passes along the right of a street or roadbed. It will be obvious that should apparatus be desired for doing left hand plowing, a mere reversal of corresponding parts will achieve this result Without the exercise of invention. So far as use with a main mold board pivoted at any point between its ends is concerned, it will be, seen that an auxiliary mold board could be mounted on either end of such a main mold board and operated as disclosed herein within the scope of the present invention. But in connection with blades pivoted in this manner it is to be noted that the increase in transverse footage occupied by such blades arises on both sides of the power vehicle instead of on only one side as in the illustrated embodiment of the present invention. This type of blade thus gives rise to the possibility of accident on two sides of the power vehicle and in addition prevents a diagonally located mold board construcedge or portion of such a construction would move outwardly while swinging to transverse position and so might strike the curbing This may be prevented within the scope of the present invention by providing the main mold board with an auxiliary mold board and operating ram at both ends and, for example, providing the necessary fourth rarn corresponding to but functioning in'reverse direction to that of the ram 38 by reason of being at the opposite side of the pivot, there being also provided a second valve (V) and its various reservoir and tubing connections corresponding tothose herein shown, the handle (53) of the second valve beingoperatively connected to the handle 58 shown so that the two valves may be operated simultaneously, and the two valves being both connected to the pump P.

Nothing hereinstated is to be interpreted as limiting the present invention to use in connection with the particular apparatus herein shown and described or to the conjoint use of all the features herein shown and described or to the particulars of the construction herein shown and described. They may be variously modified within the skill of the artisan without departing from the true scope of the actual invention, the characteristic features of which are set forth in the following claims which intentionally contain generic terms that'are inclusive of various modifications with respect to the use and structure of actual physical embodiments of the present invention.

What, is claimed as new is:

1. For use in material dislodging apparatus, a construction comprising a plurality of material dislodging blades slidably secured together, each dislodging blade being provided with a depending scraper blade, and at least a portion of the bottom edge face of one of the dislodging blades resting upon the top edge face of the scraper blade of another of the dislodging blades.

2. In, an apparatus for dis-lodging material, the combination with an axially vertical pivot, a mold board construction mounted for swinging movement as a whole about the pivot and provided with a plurality of relatively slidable dislodging blades adapted to overlap each other,

about the pivot to vary the over-all length of the dislodging blades.

3. In an apparatus for dislodging material, the combination with a mold board construction swingably mounted on an axially vertical pivot and provided with a plurality of dislodging blades relatively slidable one along another, of means for simultaneously swinging the mold board construction as a whole about the pivot and relatively sliding said blades.

4. In an apparatus for dislodging material, the combination with a mold board construction swingably mounted on an axially vertical pivot and provided with a plurality of dislodging blades relatively slidable one along another, of fluid pressure means for simultaneously swinging the mold board construction as a whole about the pivot and relatively sliding said blades.

5. In an apparatus for dislodging material, the combination with a mold board construction swingably mounted on an axially vertical pivot and provided with a plurality of dislodging blades relatively slidable one along another, of hydraulic means for simultaneously swinging the mold board construction as a whole about the pivot and relatively sliding said blades.

6. In an apparatus for dislodging material, the combination with a main dislodging blade, a second dislodging blade slidably movable along the main blade, a pivotal mounting for the main blade, means operable to move the second blade along the main blade, and means operable to swing the main blade about thepivotal mounting, of a single control for said two operable means whereby the second blade is moved along the main blade simultaneously with the swinging of the main blade.

7. In an apparatus for dislodging material, the combination with a main dislodging blade, a second dislodging blade slidably movable along the main blade, a pivotal mounting for the main blade, a ram operable 'to swing thema'in blade about the pivotal mounting, and means for actuating the ram, of a second ram operatively connected to said actuating means for moving the second blade along the main blade during the swinging of the latter.

8. In an apparatus for dislodging material, the combination with a push frame, a main dislodging blade, means for pivotally connecting the main dislodging blade to the push frame, a second dislodging blade supported for movement along the main blade, a ram connecting the main and second blades for moving the latter along the former, and a second ram connecting the main blade and the push frame for pivotally swinging the main blade, of means for actuating the two rams simultaneously.

9. In an apparatus for dislodging material, the combination with a pivot, a longitudinally expansible and contractible dislodging blade construction mounted on the pivot so that said construction may be swung toward and away from a position in which said construction is located transversely to the line of progress, and means for swinging said construction on said pivot, of means for lengthening said construction while it is swinging away from said transverse position and for proportionately shortening said construction while it is swinging toward said transverse position.

10. Apparatus as set forth in claim 9, characterized by the fact that the last named means there recited is operatively connected to the swinging means there recited.

11. Apparatus as set forth in claim. 9, characterized by the fact that the last named means there recited is hydraulic.

12. Apparatus as set forth in claim 9 characterized by the fact that the last named means there recited is fluid pressure means.

THOMAS J. BALL. 

